A shark advice was issued on Wednesday after a number of shark sightings off the popular tourist destination.

Since December 29 – 19 sharks have been reported.

These include Bronze Whalers, Hammerheads and a Tiger Shark. Other sharks were not identified.

To reduce the risk to people, surf life savers closed beaches as needed.

Swimmers are asked to obey beach closures and warning signs placed at beach access points where they have been closed.

An American tourist was killed by a shark off the island while diving in 2011.

All shark sighting information reported to Water Police is provided to response agencies and to the public on the SharkSmart website and the Surf Life Saving WA Twitter feed.

The Department of Primary Industries and Regional Development is working with the Rottnest Island Authority to monitor and report shark sightings and detections in the area and Rottnest Island Authority rangers are managing beach closures.